Subrat Kumar Sahoo
Former Asst. Manager – Technical,
Network 18.

3D TV – An Extra Dimension In Viewing TV Programs

Human eye prefers to have a real-looking one as long as video or picture is concern. To achieve reality feeling from a normal video, 3D technology is capable of providing pleasantry sensation to the eye. Television broadcasts in 3D promise to give people an extra dimension in viewing television programs. The stereoscope (3D) was invented by Sir Charles Wheatstone and stereoscopic 3D TV was demonstrated successfully by John Logie Baird for the first time.

3D video is nothing but the representation of picture details in 3-dimensional space that has an extra axis detail with respect to conventional video. 3D television provides depth perception to the viewers that give a feeling of real world picture with extra distance details. Depth perception refers to the ability of human eye to achieve the environment in three dimensions and the real distance of any object.

Both eyes of human being have a little different resolution and hence each eye can hold slightly different perception of the object. By blending these two images captured by each eye, human brain produces a single image with real depth. 3D TV technology adopts the same principle i.e. conveying little different images to left and right eye of the viewer. Human brain has got cheated into thinking that it is looking at a 3D object.

The foremost necessity of 3D technology is to display offset images and these images are filtered separately to left and right eye. Basically in order to achieve 3D picture, two methods have been implemented; with eye glass and without eye glass. The viewer wears an eye glass to filter separately offset images to each eye. Pretty Rubbish, Polarized 3D technology, Active 3D technology using shutter glass are some used with glass 3D technology. For without eye glass, the light source separates the images directionally into the viewer’s eye. Parallax Barrier technology, Window wall, VLC (visible light communication) are some used without eye glass 3D technology.

The implementation of 3D for live television streaming increases the broadcast cost because two different bands are used for a single television channel. The challenge for TV engineers is to increase the number of views and eliminate the gaps between each. The current form is nine views with around 15 needed to make the TV comfortable enough to watch. Another challenging factor is the viewing angle. The 3D effect is destroyed outside of a 40 degree area in front of the screen; hence there is no chance of a crowd gathering around to watch an auto-stereoscopic 3D TV.

For stereoscopic video coding and distribution formatting many techniques are adopted like anaglyph, quincunx, and 2D plus depth. MPEG has been researching multi-view, stereoscopic, and 2D plus depth 3D video coding that will enhance the digitalization process of the 3D content. HDMI 1.4 has defined a number of 3D transmission formats. DVB has standardized DVB 3D TV specification for packaged media, the 3D Blu-Ray player needs to be connected with 3D TV; HD-STB has to be connected with 3D TV for 3 dimensional broadcast; and through an in-built tuner and decoder, 3D TV is capable of receiving a 3 dimensional television broadcast directly.

Approximately one-fourth of the people are having very weak stereoscopic vision and thus depth perception is nullified for them. Such people are unable to view the 3D video properly while watching programs on a 3 television set. While watching 3D films, some viewers complained about noticing headache, eye strain, seizures, motion sickness etc.

In the first half of 2008, 3D television channel, BS11 was telecast by Japanese Broadcasting Corporation. As on date SKY 3D, 3flow, HIGH TV 3D are some 3D content transmitting television channels. Research is in progress make to dominant the ill effects and enhances the popularity of 3D television by many organizations like SMPTE, CEA, 3D @ Home Consortium, ITU & ETC, DTG etc. LG, Samsung, Sony, Panasonic, Sharp Aquos are some companies manufacturing 3D television sets.

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